Playing on Mexico's national soccer team helped Alina Garciamendez improve her skills against world-class competition. It also has helped keep her grounded.

"We're usually the underdog," she said.

Her other team is hardly ever the underdog.

That's the No. 1-ranked and defending national champion Stanford Cardinal (20-1-1), who play No. 6 UCLA (18-2-2) Friday at 7 p.m. in the NCAA quarterfinals. Stanford's Cagan Stadium is sold out for the match, which will determine a berth in the College Cup, soccer's Final Four, in San Diego next weekend.

Garciamendez has started every match since she arrived on the Farm in 2009. That's a school-record 100 matches. The central defender has been the rock of the defense through three previous trips to the national finals.

She plans to become a dentist. For the time being, she's more likely to dislodge somebody's teeth as one of the most physical players on the field. Yet her coaches and teammates describe her as the All-American woman. She just happens to moonlight for Mexico.

"She's the nicest person ever," goalkeeper Emily Oliver said. "She's level-headed but will get you fired up when she needs to."

The 5-foot-8, three-year co-captain moves forward on set pieces. That helps explain why her six goals is the third highest total on the team. On Oct. 26, her golden goal in the 103rd minute beat USC 1-0 at the Los Angeles Coliseum, where the bandbox field dimensions made a mess of the match for both teams.

Coach Paul Ratcliffe called her "one of the best headers of the ball in the college game" and thinks her international experience has paid big dividends for his team. "Her understanding of the game is like a professional's understanding of the game. Her intelligence on the ball and her decision-making are things that are very difficult to teach a young player, and she has all those qualities at a young age."

Although she was born in Los Gatos, when her father was in graduate school at Stanford, she grew up in Texas. She's part of a recruiting pipeline from the Lone Star State that has brought Stanford such athletes as football's Andrew Luck and Stepfan Taylor and basketball's Ogwumike sisters.

Her teammates call her "Selena" after another Texan, singer-actress Selena Gomez. "But I can't sing," she said.

She played for the United States Under-16 team, but after she tore her ACL, she never got a whiff again from U.S. Soccer.

"We e-mailed the manager to see if he could come look at me in a tournament," she said. "They didn't want anything to do with me."

Because her parents, Edsel Garciamendez-Budar and Lisi Rowold-Garciamendez, were born in Mexico City, she has dual citizenship. As a high school junior in Dallas, she landed a tryout with Mexico's under-17 team and has been playing for that country ever since.

She has 30 appearances with the senior national team, including the 2011 World Cup in Germany. Ties with England and New Zealand helped Mexico to one of the best showings ever for its women's team.

A loss to Canada in the CONCACAF semifinals of Olympic qualifying kept Garciamendez out of this year's London Games. "I thought we played our best game in that tournament," she said. "It was unlucky."

Ratcliffe thinks she'll have a long career for Mexico. Maybe not. She'd like to play in one more World Cup, but after playing abroad next year, she'll probably attend dental school.

"I love playing for Mexico," she said. "The whole environment is awesome."

Briefly: Stanford seeks its fifth straight trip to the College Cup. ... UCLA's Zakiya Bywaters, the Pac-12 Player of the Year, led the conference with 15 goals. ... Stanford has beaten UCLA in their last six metings, including a 2-1 win on Oct. 28.